// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_LOG_TRACE_NET_LOG_OBSERVER_H_
#define NET_LOG_TRACE_NET_LOG_OBSERVER_H_

#include "base/macros.h"
#include "base/trace_event/trace_log.h"
#include "net/base/net_export.h"
#include "net/log/net_log.h"

namespace net {

// TraceNetLogObserver watches for TraceLog enable, and sends NetLog
// events to TraceLog if it is enabled.
class NET_EXPORT TraceNetLogObserver
    : public NetLog::ThreadSafeObserver,
      public base::trace_event::TraceLog::EnabledStateObserver {
public:
    TraceNetLogObserver();
    ~TraceNetLogObserver() override;

    // net::NetLog::ThreadSafeObserver implementation:
    void OnAddEntry(const NetLog::Entry& entry) override;

    // Start to watch for TraceLog enable and disable events.
    // This can't be called if already watching for events.
    // Watches NetLog only when tracing is enabled.
    void WatchForTraceStart(NetLog* net_log);

    // Stop watching for TraceLog enable and disable events.
    // If WatchForTraceStart is called, this must be called before
    // TraceNetLogObserver is destroyed.
    void StopWatchForTraceStart();

    // base::trace_event::TraceLog::EnabledStateChangedObserver implementation:
    void OnTraceLogEnabled() override;
    void OnTraceLogDisabled() override;

private:
    NetLog* net_log_to_watch_;

    DISALLOW_COPY_AND_ASSIGN(TraceNetLogObserver);
};

} // namespace net

#endif // NET_LOG_TRACE_NET_LOG_OBSERVER_H_
